Few Jewish immigrants have wielded the cultural power of Louis B. Mayer, head of pre-television America’s greatest cinematic dream factory, MGM Studios. Louis B. Mayer: King of Hollywood is an illuminating look at a man who overcame humble origins to rule over movie stars and the personal price he paid for that success.

“I have abundant reason to cherish the blessings of our democracy and to resist with all my strength any effort to undermine it,” Mayer said, as part of his testimony before Senator Joseph McCarthy’s House Committee on Un-American Activities – one of the few existing recordings of Mayer’s own voice.

This is the story of a man who rarely emerged from behind the carefully-constructed wall of his studio kingdom. That studio defined what many consider to be Hollywood’s “Golden Age.” But though he is often remembered as the all-powerful sculptor of silver screen glitz and glamor, this film shows Mayer in a far more personal, and often unflattering light.

With a wealth of photos and interviews with family and colleagues, we see the foibles and insecurities of a very successful immigrant whose traditional “family values” drove the “star system” of Hollywood studios. Born in Russia, but reared within the Jewish immigrant enclave of St. John, New Brunswick in Canada, Mayer was raised to believe that the father figure was the indisputable head of any family. Later, as General Manager of MGM, he often played this patriarchal role to the hilt in order to control the lives and careers of stars like Clark Gable, Joan Crawford, Spencer Tracy and Judy Garland. Mayer’s protective watch included building influence among political, religious and military figures, while also getting police and newspapers to turn a blind eye to any scandals.

“L.B. Mayer had some powerful friends,” recalls his grandson, Daniel Mayer Selznick. “When they say he looked after and protected you, this was a long, wide protective arm. Some people loved it. Some people hated it.”

Those who chafed the most were his daughters Edith and Irene. Despite his efforts to have them stay clear of the movie business and become traditional Jewish housewives, they rebelled and married film producers. Studio success and a hefty paycheck that made him “America’s highest paid employee” had changed the family forever, something not lost on Mayer’s father Jacob, a lover of Talmudic lore who had once supported the clan as a peddler.

“God has made you treasurer,” the elder Mayer is said to have told his son. “Every family has one.”

Continuing to earn that wealth was a far more uncertain proposition than many viewers might have previously realized. Mayer was only granted one-year contracts from MGM, and their continuity rested firmly on his ability to judge the ever-changing tastes of the American film goer. He was greatly aided in this endeavor by the production talents of another member of Jewish film royalty — Irving Thalberg. The savvy young wunderkind, whose intellectual leanings balanced Mayer’s more populist tastes, helped produce the studio’s most successful period, before illness sent Thalberg to an early death.

Mayer’s closing years at MGM were not happy ones. After divorcing his invalid wife, Margaret, for the pursuit of younger women, Mayer ruined his relationship with his children. Then, entering his 70s and increasingly out of touch with his audience, he was finally forced out as studio chief after three decades in the post.

Despite all the turmoil, Louis B. Mayer has left a lasting legacy of MGM films that are loved by people from all walks of life. His greater achievement, however, may be that of a reminder to Jews and immigrants of the possibilities and the pitfalls that come with achieving the American Dream.